1. Field of Art
This invention relates to apparatus for moving particulate material such as alumina toward the outlet of a bin or along the length of an elongate feeder duct.
2. Description of the Prior Art
Systems for conveying particulate material and for discharging such material from bins or other containers are well known in the art. For example, U.S. Pat. No. 3,681,229 discloses an alumina feeder in which a gas permeable hose is disposed in a conveyor duct for fluidizing alumina in the duct so the alumina will flow through the duct. That patent further discloses metering apparatus in which alumina is fluidized to cause it to move therethrough.
U.S. Pat. No. 3,212,624 discloses a vibratory screw feeder in which an auger pushes particulate material through a casing and which includes leaf springs mounted on the casing to vibrate it to produce a uniform density of material and more accurately control flow. U.S. Pat. No. 3,166,222 discloses a vibratory bin agitator to promote free uniform flow of powdery material from the bin. An aeriform fluid may be supplied through the stem of the vibrating mechanism to discharge into the material to further inhibit any tendencies of the powdery materials to bridge in the bin.
U.S. Pat. No. 3,754,685 is addressed to a discharge apparatus in which a cable having a plurality of spaced apart cone-shaped conveying elements on it is reciprocated back and forth to both agitate and convey material. The patent discloses use of such apparatus for conveying materials such as logs or wood chips. U.S. Pat. No. 2,607,514 is of interest for its disclosure of a powder dispenser with a conical coiled spring having its base fixedly secured and its apex pinned to the upper end of a rod which is reciprocated vertically to agitate powder and prevent it from being caked in the container.
Despite the numerous systems that are available for moving particulate materials, an improved system is desired which will convey powdery particulate material with a minimum of dust being dispersed into the atmosphere while also avoiding the other problems of bridging and non-uniform feeding rates.